Triaxial acceleration sensors, in particular triaxial micromechanical acceleration sensors, are needed for applications in entertainment and automotive electronics. A maximally compact design of the acceleration sensors is considered desirable in those cases.
The basic principle of micromechanical acceleration sensors is that a seismic mass is movably supported with respect to stationary electrodes on a substrate with the aid of a suspension. The seismic mass and the stationary electrodes form one or more capacitors. A deflection of the seismic mass caused by an acceleration acting on the micromechanical acceleration sensor results in a change in the capacitances of these capacitors, which may be detected and represents a measure of the magnitude of the effective acceleration. To avoid zero deviations, capacitance changes are preferably evaluated differentially.
Conventionally, triaxial acceleration sensors are implemented using three sensor cores which are independent of each other and have separate seismic masses, which are situated next to each other on a shared chip. This results in large space requirements and comparatively large acceleration sensors.